• Elastomers and Composites
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• v.31 no.2
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• pp.111-121
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• 1996

The characteristic of silicone rubber can be seen from its resistance to both low and high temperature, whereas HNBR is resistant only in high temperature moderatly although it can be compounded to give good tensile properties, good oil resistance while silicone rubber severely lacks in these qualities. This study was initiated a balance of properties by blending HNBR and silicone rubber which is not considered for commercial blending; blends of HNBR with silicone rubber tend to show immiscible due to dissimilar nature of silicone and HNBR, the possibility of phase separation cannot be ruled out, in unfilled system after vulcanisation leading to premature failure. Attempt has been made to improve compatibility and minimise the layer seperation by the use of compatibilizer. Both filled and unfilled systems, in presence and absence of compatibilizer have been studied. Improvement in tensile properties of the blends or are observed as compared to the non-blended rubber. Different ratios of HNBR and silicone rubber are represented in this study. Blends of HNBR with silicone rubber were immiscible system. The tensile strength increased with filler loading.

• Economic and Environmental Geology
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• v.54 no.1
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• pp.105-115
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• 2021

The geological CO2 sequestration in underground geological formation such as deep saline aquifers and depleted hydrocarbon reservoirs is one of the most promising options for reducing the atmospheric CO2 emissions. The process in geological CO2 sequestration involves injection of supercritical CO2 (scCO2) into porous media saturated with pore water and initiates CO2 flooding with immiscible displacement. The CO2 migration and distribution, and, consequently, the displacement efficiency is governed by the interaction of fluids. Especially, the viscous force and capillary force are controlled by geological formation conditions and injection conditions. This study aimed to estimate the effects of surfactant on interfacial tension between the immiscible fluids, scCO2 and porewater, under high pressure and high temperature conditions by using a pair of proxy fluids under standard conditions through pendant drop method. It also aimed to observe migration and distribution patterns of the immiscible fluids and estimate the effects of surfactant concentrations on the displacement efficiency of scCO2. Micromodel experiments were conducted by applying n-hexane and deionized water as proxy fluids for scCO2 and porewater. In order to quantitatively analyze the immiscible displacement phenomena by n-hexane injection in pore network, the images of migration and distribution pattern of the two fluids are acquired through a imaging system. The experimental results revealed that the addition of surfactants sharply reduces the interfacial tension between hexane and deionized water at low concentrations and approaches a constant value as the concentration increases. Also it was found that, by directly affecting the flow path of the flooding fluid at the pore scale in the porous medium, the surfactant showed the identical effect on the displacement efficiency of n-hexane at equilibrium state. The experimental observation results could provide important fundamental information on immiscible displacement of fluids in porous media and suggest the potential to improve the displacement efficiency of scCO2 by using surfactants.

• Journal of Ship and Ocean Technology
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• v.7 no.4
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• pp.32-40
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• 2003

Numerical simulation code is developed to study the formation of liquid drops from a nozzle into another quiescent liquid. The Navier-Stokes equations for two immiscible, incompressible, Newtonian fluids are solved on a fixed, staggered grid of cylindrical axisymmetric coordinates. Interfacial motion is captured using a Front-Tracking Method. The time variation of interfacial shape simulated by the code is in excellent agreement with experiments. Simulation results show that the viscosity ratio affects the size of the satellite drops.

• Proceedings of the Membrane Society of Korea Conference
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• 1996.04a
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• pp.55-56
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• 1996

Heterophase polymer system has been attractive for a potential applicability to gas separation membrane material. It has been known that there is a trade-off between gas permeability and its selectivity in common polymers. Therefore, the heterophase polymer can be an alternative for a gas separation membrane material because its transport properties can be readily controlled by blending of two different polymers. The transport properties of immiscible polymer blends strongly depend upon the intrinsic transport properties of corresponding polymers. Another important factor to determine the transport properties is their morphology: volume fraction, size and shape of dispersed phase. Although the effect of the volume fraction of the dispersed phase on the transport properties has been widely investigated, the size and shape effects have been paid attention very much. In an immiscible polymer blend of two polymers, its morphology is primarily controlled by its volume fraction of dispersed phase. Therefore, the effect of the size of the dispersed phase can be hardly seen. Therefore, a block copolymer has been commonly employed to control their morphology when each block is miscible with one or the other phase. In this work, gas transport properties will be measured by varying the morphology of the heterophase polymer membrane. The transport properties will be interpreted in terms of their morphology. The effect of the volume fraction of the PI phase and, in particular, its size effect will be investigated experimentally and theoretically.

• KSBB Journal
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• v.27 no.4
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• pp.207-214
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• 2012

Emulsions are mixture of immiscible liquids in which one is dispersed in all over the other. They have been applied to many applications including cosmetics, foods, drug delivery system (DDS), fine chemicals, and chemical separations. Especially, emulsion technology is one of the most useful technique to formulate cosmetics such as eye cream, foundation, and foam cleansing. In general, the emulsions can be generated by mechanical agitation of two immiscible fluids. However, the emulsions obtained by conventional method have limited in stability, monodispersity, and complicate process. We describe here preparation techniques of representative cosmetic emulsions such as liposome, liquid crystal emulsion, nanoemulsion, multiple emulsion, and pickering emulsion. Furthermore, various factors which can control the physical properties of each cosmetic emulsions are briefly discussed.

• Korea-Australia Rheology Journal
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• v.13 no.4
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• pp.189-196
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• 2001

The phase morphology is an important factor in the rheology of immiscible polymer blends. Through its size and shape, the interface between the two phases determines how the components and the interface itself will contribute to the global stresses. Rheological measurements have been used successfully in the past to probe the morphological changes in model blends, particularly for dilute systems. For more concentrated blends only a limited amount of systematic rheological data is available. Here, viscosities and first normal stress differences are presented for a system with nearly Newtonian components, the whole concentration range is covered. The constituent polymers are PDMS and PIB, their viscosity ratio can be changed by varying the temperature. The data reported here have been obtained at 287 K where the viscosities of the two components are identical. By means of relaxation experiments the measured stresses are decomposed into component and interfacial contributions. The concentration dependence is quite different for the two types of contribution. Except for the component contributions to the shear stresses there is no clear indication of the phase inversion. Plotting either the interfacial shear or normal stresses as a function of composition produces in some cases two maxima. The relaxation times of these stresses display a similar concentration dependence. Although the components have the same viscosity, the stress-component curves are not symmetrical with respect to the 50/50 blend. A slight elasticity of one of the components seems to be the cause of this effect. The data for the more concentrated blends at higher shear rates are associated with a fibrillar morphology.

• Journal of the Korean Ceramic Society
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• v.30 no.12
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• pp.1071-1079
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• 1993

Interaction of alkali oxides and SO3 and C3S formation and microstructure was studied using K2CO3 and Na2CO3 as alkali sources and (NH4)2SO4 for SO3. When SO3/K2O=1.43 as mole ratio, K2O and SO3 react to form K2SO4, this phase is immiscible with other oxide melt and thus could not affect C3S formation as well as its microstructure. In a condition of SO3/K2O 1, C3S crystals were round and grown in a much larger size. With addition of Na2O and SO3 by only 1wt% each, C3S formation was strongly hindered. Since C2S was stabilized by Na+ and SO4-2, it could not react to give C3S formation. However in the condition of SO3/Na2O=1.43, a little amount of C3S was formed. It is considered that small amount of Na2SO4 was formed, this phase was immiscible with clinker liquid, and the C3S crystals were formed locally in the liquid part of relatively low Na2O and SO3 compositions. These crystals had irregular and rough surfaces and contained more inclusions than those grown from K2O.SO3 system.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.16 no.5
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• pp.210-215
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• 2006

Mechanical alloying (MA) by high energy ball mill of pure copper and niobium powders was carried out under the Ar gas atmosphere. The supersaturated solid solution can be produced in the range up to $Cu_xNb_{100-x}$(x=5-30) by MA for 120 hrs, as demonstrated by X-ray diffraction, DSC analysis and the electronic studies through a change in the superconducting transition in the low-temperature specific heat. The $Cu_{30}Nb_{70}$ samples ball-milled for 120 hrs exhibit only a broad exothermic heat release. The total energy, ${\Delta}H_t$ accumulated during MA far the mixture of $Cu_{30}Nb_{70}$ powders increased with milling time and approached the saturation value of 7.5 kJ/mol after 120 h of milling. It can be seen that the free energy difference between the supersaturated solid solution and the mixture of $Cu_{30}Nb_{70}$ powders is estimated to be 7 kJ/mol by Miedema et al. Hence it is thermodynamically possible to assume the formation of a supersaturated solid solution phase in this system.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.144-147
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• 2003

In this study, the mass transfer behaviors of phenanthrene, anthracene, and pyrene in soil slurry reactor (SSR) using two-liquid phase (TLP) system were investigated. The mass transfer ratio and rate of PAH in the TLP system using light paraffine oil, which has the highest solubility of PAH, were influenced by the amount of light paraffine oil and mixing speed. When the amount of light paraffine oil decreased from 15 % to 2.5 % (v/v), the mass transfer ratio of anthracene decreased significantly compared with that of phenanthrene and pyrene. As mixing speed increased, the initial mass transfer rate of PAH within 1 day was enhanced. However, each final mass transfer ratio of three PAHs after 5 day was similar irrespective of mixing speed.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.170-170
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• 1999

We studied Nb growth mode on Cu(100) surface by scanning tunneling microscopy (STM) at room temperature. Nb/Cu is immiscible at room temperature and thus is an ideal system for studying surface alloy formation. Initially deposited Nb atoms are incorporated subsurface on Cu(100). After annealing, they are preferentially found at step edges and appear as bright dots surrounded by dark rings. Ordering emerges from step edges as annealed. Ordered ({{{{ SQRT { 5} }$\times${{{{ SQRT { 5} }}}})R 26.6$^{\circ}$phase Nb structure is formed at $\theta$<0.2ML after annealing to 50$0^{\circ}C$. At higher coverage, $\theta$>0.25, annealing leads to p(2$\times$2) phase. due to large mismatch in lattice parameters, the domain is limited to a few tens of nm2. Growth kinetics of the system will be discussed.